Blind stitch sewing machine



1952 F. MIKOLAS BLIND STITCH SEWING MACHINE 2 SHEETS-SHEET 1 Filed Feb. 28, 1948 F. MIKOLAS BLIND STITCH SEWING MACHINE Nov. 18, 1952 2 SHEETS-SHEET 2 Filed Feb. 28, 1948 Zm ew far Fran z M/ka/a 5 Patented Nov. 18, 1952 UNITED STATES PATENT OFFICEv Application February 28, 1948, SerialNo. 12,076 In Austria March 12, 1946 10 Claims. '1

The invention relates to machines or accessory appliances for sewing machines for producin blind stitch or pique seams in which a blind stitch needle passes-at every working strokethrough a thread loop formed by a looper as well as through the work temporarily lifted by means of a fabric bender whereupon i. e. after the return stroke of the needle, the feeding motion of the work is carried out.

The machines and devices hitherto disclosed for this purpose-irrespectively of whether the looper travels along a path composed of rotary and longitudinal motions, or whether it executes a simple oscillating movement along a circular arc -are all characterized by the looper itself conveying the thread picked up fromthe needle in the shape of a loop to the needle entering point and holds it there until the stitch is made. For this purpose the looper must be provided with two nose-shaped catchers or pQinted grippers for holding the loop, and should additionally execute a motion enabling it to pass from the needle exit point directly over the fabric roll produced by the fabric bender, and then again to descend to the needle entering point. As, however, in this case the looper is open towards the fabric to be sewn, there is, the danger that the thread loop may be stripped off from the looper, and that the latter may get stuck by clamping, particularly when working, fabrics of varying thickness e. g. padded ones. The passing of "the looper over the fabric roll isrealized in pique devices, having a looper oscillating along a circular'arc, in such a manner that the latter executes its oscillating motion in a plane chiefly :1

located behind the needle plane and slanting upwards in the fabric feeding direction so as to compel the looper first to mount and then to descend. With an arrangement of this kind, however, the conveyor cannot be sufficiently approached to the needle, and for this reason the stitching of the work can only be started at a certain distance from the fabric margin.

The object of the invention is a blind stitch and piqu device which may be used as a self contained machine, or as an accessory appliance for sewing machines, said device eliminating the above mentioned drawbacks by fixing in the range of the needle path a loop catching nib (loop catcher) by means of which the thread loop supplied to it by the looper is located above and below the needle guide for the subsequent throughstitch of the blind stitching needle. As not only the loop catcher but also the looper, preferably oscillating in a manner known along a circular arc, are separated from the work by a cover plate over the whole length of the mov ing range, the formation of the loop and the stitch are perfectly independent of the nature and the thickness of the work. Besides, the looper path, ending with the thread loop being picked up by the catcher, is located in front of the needle plane, except the portion of the path necessary for picking up the thread from the blind stitching needle, which renders possible a conveying arrangement permitting of seaming the workpiece from its very margin.

The drawing represents, by way of example, two embodiments of the subject matter of the invention, Fig. 1 being a lateral elevation, partly in section, of a pique device employed as an accessory to a sewing machine, immediately after the beginning of the return motion of the needle, whereas Fig. 2- shows the same device at the moment at which the needle begins its subsequent forward stroke. Fig. 3 is a longitudinal .section through the pique device, seen from the right-hand side of Fig. 1, Whereas Fig. 4 is a section taken along the line IV-IV of Fig. 3. Fig. 5 is a lateral elevation, and Fig. 6 a front elevation of the looper. The Figs. 7 and 8 are a lateral elevation, partly in section, and a plan,

diagrammatically showing the stitching plate together with the fabric bender, and its drive. Fig. 9 represents a blind stitching and piqu machine according to the invention in front elevation seen from the operators side with a partial section through the fabric guiding foot, whilst Fig. 10 is a lateral elevation of the same embodiment. The Figs. 11 and 1 2 are views in full size of the stationary fabric guiding foot (cover plateklii 11. ei g a pl n showin the ma n in which the stitches are made, whereas Fig. 12 is a section taken on the line 2sIII- -XII ofFig. 1 1.

The pique device represented in the Figs. 1-3, suitable for stitching through and, in particular, for blind stitching, is provided with a presser foot 4 (Figs. 3, 4) fastened by means of a screw 2 to a presser-bar 3. The foot part of the presser foot, preferably fitted with a level bottom, is ope posed to the fabric feeding direction :0, its upper side 4a, 4b obliquely sloping towards its bent-up free end, so as to form a step i. In the presser 'foot 4 a needle groove 6, curved in its longitudinal direction, is provided below the step I trans versally to the feeding direction a: of the workpieces 5 to be seamed (Figs. 1, 2), said channel serving as a guide for the blind stitching needle I, and being .interrupted on a part of its length by a central recess 8 (Fig. 4) passing through the presser foot 4. To the end of the needle groove 8 a channel 9 (Figs. 3 and 4) is directly joined, obliquely opening into the presser foot bottom, so as to create the necessary space for the root of the thread loop ii) forming. The margin of the foot recess 8, facing the user of the sewing machine, is cambered and passes, towards the entrance point of the needle 1, into a surface depression II bordered by an arc, so that between the latter and the front part of the needle groove 6 a loop catching nose I2 is formed at the border of the foot recess 3. In order to enable this loop catching nose I2 (Figs. 1-4) to accomplish its task it is undercut to form a rest I3 for the lower thread part of the loop I0, said rest beginning at the surface depression I I, and the recess 8, and reaching below the needle groove 6. Besides, said nose is made to protrude in the upward direction somewhat beyond the edge of the needle groove 6, so that the upper thread part is freely laid above the needle groove 5, in consequence whereof the blind stitching needle I may freely enter into the thread loop ID.

The blind stitching needle I is arranged on an oscillating arm I6 formed as a part of a circular arc by means of a needle clamp I provided with the thread guides I 4 (Figs. 1 and 2), said arm executing oscillating movements about a journal bisecting the axis of the presser-bar 3, and being located in parallel to the fabric conveying direction X (Figs. 3 and 4). In order to attain this object a clamping (gripping) piece I'l, slid on the presser-bar 3 just above the presser foot 4, is fastened in such a manner that its medium part is divided into two lateral cheeks Ila by means of a slot arranged in parallel to the axis of rotation of the oscillating arm I8, one of said cheeks being split by a transverse slot I8 into an elastic lug, and fixing the clamping piece I! on the presser-bar 3'when tightening a tension screw I9 passing through the cheek nu. This clamping piece I! serves as support for the oscillating'arm I8 by passing into a stirrup (Figs. 1, 3) which laterally embraces the clamping piece I1, said stirrup engaging on both sides a center-mark like depression of the clamping piece I! by means of a pointed and threaded pin 22, secured in its position by a'nut 2|. In this manner the tilting motion of the oscillating arm I3 is made possible. The drive of the oscillating arm Hi can be realized in different manners. With the pique device, designed as accessory for the usual sewing machine according tocthe I embodiment illustrated, said drive is derived from the needle bar 23 of the sewing machine for which purpose an arm 24, clamped, to the. needle bar 23, is connected to the oscillating arm I6 by way of a link 25.

A rotaiybolt 28, provided at its upper part with a bevel gear wheel 21, is journalled at its one end in an arm 26 obliquely sloping at the upper end of the presser foot 4, and at its other end in the correspondingly inclined upper side 4a, 4b of the presser foot 4, for which purpose the lower pointed bolt end engages a center-mark like depression of the presser foot whilst a threaded pin 33 passing through the arm and securely fixed by the nut 29 rests with its point in a needle groove 5. Consequently, the upper bearplane of the needle groove 6, whilst its lower bearing is placed behind said plane. Moreover, the rotary bolt 28 carries a clamping (gripping) body 3| similarly shaped as the clamping body I! which takes up in a bore the shaft 32 of the looper 33, designed at the same time as thread spreader. The fixation of the clamping body 3| to the rotary bolt 28 and. to the looper shaft 32 in the clamping body 3| is effected by the clamping screw 34 (Figs. 2, 3).

With the bevel gear wheel 21 a toothed are 35, fixed to the oscillating arm I6, is made to register, whereby'a movement of oscillation reaching to about 135, is imparted to the rotary bolt '28 and consequently to the looper 33 by the motion of the needle bar 23, said motion taking place counterclockwise during the forward stroke of the blind stitching needle I, and clockwise during the return stroke for the machine being contemplated from above (arrow 1/, Fig. 4). The oscillation range and the oscillation position of the looper 33 are determined in such a manner that at the end of its return stroke (position Fig. 1) it recedes completely behind the needle groove 6, whereas during the forward stroke it lays over the nose-shaped catcher I2 the thread loop I0 picked up by it (position Fig. 3).

The looper 33 projecting as small foot from an oblique undercutting 36 (Figsp5, 6) of the shaft 32, and terminating in a point 31 has, seen in plan, approximately the shape of a scalene triangle, whose smallest angle determines the point 3'! of the looper. Together with the adjoining side of the triangle adjacent to the right angle, this-point 31 is unilaterally inserted in an even-faced upright lateral wall 38 of the looper 33, whereas the hypothenuse, somewhat curved outwardly in an arc-shapedmanner, forms the other lateral border edge 33 of the bottom to which a slight convexity is imparted, and which preferably slopes somewhat towards the point 31, but is more inclined towards the lateral wall 38. Beginning from the border edge 39 the said bottom passes into the upper side of the looper by convexly cambering up to the lateral wall 38 e. g. along a part of the surface of a cone. so that also the upper part beginning from the point 31 slantingly ascends towards the shaft 32. and is made to enlarge laterally. The looper 33 is fastened in such a manner in the clamping body 3| that its even lateral wall 38 is directed inwardly i. e. towards the rotary bolt 28, whereas its bottom 48 leaves open a slot between the looper 33 and the presser foot 4, sumcient for the unhampered passing of a thread even in the inclined position of the looper. caused by the oblique position of the rotary bolt 28. The extreme slanting position is obtained, when the looper 33 together with the shaft 32 attains its foremost position in respect to the user of the machine.

The pique device comprises further a fabric bender 42 (Figs. 1, '7 and 8) which executes a reciprocating motion through an aperture of the stitching (needle) plate 4| (Figs. '7, 8) lifting the fabric and the inset parts 5 to be piqud'f within the recess 8 of the, presser foot, conveying same during the seaming action into the range of the blind stitch needle i. The drive of the fabric bender 42 is e. g. derived by way of a double-armed lever 43 from a cam 44 (Figs. 7. 8) the latter being fastened on the conveyor shaft 45, generally used in sewing machines and showing a level-faced section 48 recessed in respect to the remaining circumference which has the shape of a circular cylinder. An adjusting device, not shown in the drawing but of known absc ssa diretion of: the arrow: 2-? (Fig. 11);, the forward stroke; or: advance: of: that looper 33% is: synchronon t: started; said: stroke: being; carried out.- in: the: lockwise direction: (-arrow' Fig; 4e); thelooner grinning: from below the? portion: 05 the thread til: between. the: fabric 5: and: the..- needle eyersi'ightly above-.- theblind stitching needle 1- sei' thread;- pertionlosing; itetension. and: stand:--- ing a littlewith the blind. stitching; needle-.1 receding; This; portion, of; the; thread; [-0,- is. come plate n shiftedon the. longer 3.3 up.- toiitsv undericutting" 36; andis enlarged. and spread; out by,

same to' a wide loop 1.. A-ftehthesneedle 1, has released/the fabrics 5 therfabricbender 42 togame: withlther fabrics 5. descends, under:- the: action of' the doubleaarmed; lever 43-..reachingthe range; of. the canrsection 46, for the duration of theyfabric; conveyance by means, at the. usual transporting devices. Inconsequence; off the for, war slanting. position or; the mam bolt. 28 the 16b9,, 33 wilL. in...the.. course. of; its; iorward. stroke, fi'nallg reach a" position soi low: that the: tower: par ofithethread loop, H): is. caughtby' the rest I he. nose: [2,. said; rest, being; located; below dle. groave: 6. (Fig. 2); whereas. the. upper. portion. is; abovethe. needle. groove.

. fithasubsxduentoperatibm (op ositete-the.

arrow. 2;. Fig... 1')? off. the. needle 1? some. passes thrini'gh. the. thread"; loop. IUj and; shortly after Ward's: again" through. the" fabrics 5;. lifted by the fabric bender 2-,. whereas. the. looper 3,3. (in the opposite; direction to the? arrow. 11,1. F553,. 4). returns. intajits; initial; position. For blind. stitching. op.-- eratibns the. fabrib; bender 42. is. to bev adjusted. in; such a. manner. that. the lower fabric: is. not. en.- tirely."'stitbhedPthroughz. 'If; however; the fabric 61 free. end. a rotary" bolt; iii. whose: othe'n end. carries: pinion registeninszwitm the:v $2;- The. axis?- of rotation of; the rotary bolt". 6.5 journalist? within: the machinevheadi arm: s2 located: before; the vertical plane.- otr" the. needle. path; and? is: inclined towards the latter" as: welt as; towards the: verticaL- plane. passing through the fewest.- point'vofi the; needle path ins thedirection; of; tha fabric feed: at: as to: intersect: the nee-- 5 dlbkpath on. its: stitching-in side;

The fabric: guiding foot.- 61,,. forming; the star tionany" partof: the fabric. bender and? carrying at: its:v surface the: loop; catcher 68; is: rigidly fasttened': to. the; arm: 59;: of." the: machineieheatlf. 51

extending" towards. the? operating si'de bel'ow: thez movablepa-rt's'. of: the? pique. device: described; an ranged cm the. m'achinet-head- 51",. said. foot: sentiing': at the; same time: as. coves-plate: separating: these: parts; or? thepiqui device tram-- the: fabricsto be piqud.

The; fabric: gui'din'gi foot 6]: (see; hr particular thEEEigSi. 1 1i and 12:)? passes: fm'mthe' fastening-zv part: lixla'hprovided; on. top": with. fitting; faces; and? a. longitudinal groove; byway of recesses; in: the? direction. of: the. width; and of the thickxiesmdntjd;

. needle; path; and narrowing; in: the: di'reotl rangei of the latter; offers, in. its: wider pant; space. for the. fabrirr' conveyor-,. not; shown,v whilst; permitting: of; the: passage the: fabric: handler in"; it's.- narrovw foreepartz. Contiguous: the; fasttenin'gf part:- 6.1;: a miileds recess. amending; to; a

circular cylinder; is. provided to; correspond. to; the radius of the needle. path, the: right hamii 7 side-.borderfwall; tlfcrfacingtheihenif-umfootanart bender; 42 is also. provided. with; a groove; Within.

the. range of-theneedle groove- 6,, andliifthe. stroke;

oij the. fabric .bender 42 is, adjusted. to a. sufiici'ent length;.throughstitching' work. can. also be carried. oi'itj nnthis-device' 55. (In a transversal shaft" 56' iournalledf,

1m the. machine. head. 51., whose oscillating; mo"- a; two armedi oscillating; lever 58" is fixed. tb an arm: 51'' crime" machine-head 51' extending at his: tlieoperatihg: side, whereby the one leveifarm' carries: the needle clamp; 59" with" the" cdtveiii blind? stitching needle so and" the" thread.

feediif gi device" 6 I", whereas the" other is" provided the bevel gear segment 62 for driving the ledger" 6%.: Same is" adjustable: in the. vertical;

directibw and held by the" clamp 64', fitted to" the L inacliiheaccordingtofthe Eigs;.9i-12; may b as any: time. known. in. which. the conveyor;

derived"from'.. the main shaft in' a manner said recess andi serving: as guiding: ledge? for the. blind stitching: needle; 611;. whereami the: leftehand; sides-same" is: limitedi by? a. needle? groove: 61f; facilitating: the threading of. the. neei--- die Im this: milled: recess adapted. to; it's-i curve ture r small guiding; plates 69;. Ill-,n 141- are; fastened.

bwscrewing; to bothisidesmfftheeslot: 6111,.013 whiclt the plate m isprovided with a proi ectionesl'ightly" protruding beyond? the edge of the narrowsd sldf- D' rt. am; said: projection being. c'hamfered: 16w; d. ac in as guidefor: the lower part of r the. thread 100112 The small? plates: 150:; am 191% of. which.v the latter? is" obliquely cut" on; the" slot side; are shortened. in'. the. range. oi the. nee:- dlcr groove 61d by the width. of the. latter}. and;

' are. used. as additional" abutments. against. a. 11%: ure' of. the blind stitching. needle 60; in theafabric;

feeding! direction. Ontop the small'lplateiliflll'is chamfered' in orderto, QI'QVGHtkthB} blind-1 stitchy needle.- (it). from. impinging; even. in: case; of; a: displacement. of the fabrics; so-thatdtmam glide-oft unimpaired. 911. the left; edge pant of: the: I fabric; guidingv foot; 61: the? stationary loop; catcher Brit is;

v fastened between: the:v lint-turned: fore-mart; 61.12% 01% said. edge; and; the: needle: groove: 6H4. whereby a;

spacing. sheet- (distancesheet) 12, accountingifor's I pin- 14 bent-in its lower park-backwards to the needle path and acting as a loop holder.

The movable fabric bender horn 15, cooperating with the fixed fabric bender foot 61 is elastically journalled in respect to the latter in a fabric bender casing 11, pivotable about an axle 16 of the machine base 52, said horn being providedin the range of the needle pathwith an aperture for the. fabric bender not shown. The tiltable fabric bender holder and its driving parts are likewise lodged in the fabric bender casing 11. A strongplate spring 19 acting on the carrier' 18 of the fabric" bender casing T1 keeps it permanently in the position of use, determined by a stop 80 on the carrier 18, out of which the casing can only be lowered against the action of the spring 19 by knee drive (indicated by an operating member 8! acting on the carrier 18) for the purpose of introducing or withdrawing the fabrics to :be seamed.

' The vertical adjustment of the fabric bender casing 11, and consequently of the horn I and the fabric bender, according to the thickness of the workpieces to be dealt with, is effected by means of a set screw 82, provided with a scale which is attached to the casing base 52. Under the action of the plate spring 19 the stop 89 of the carrier 18 is permanently made to rest against the conical end 83 of said screw. By turning the screw 82, which provokes an axial displacement of the cone B3 in one or the other direction, a slight tilting motion is imparted to the carrier 18 by or against the action of the spring 19.

In order to pass readily from blind stitch to through-stitch e. g. in case of padding work the fabric bender, having an upper edge, stepped according to the needle thickness, is displaceable in its holder by a needle thickness upwards and by the said step sideways e. g. by means of a rotary eccentrical bolt, provided with a handle accessible from outside through an aperture of the fabric bender casing 11.

When the through-stitch of the blind stitching needle 50 is completed the looper 63, located at that moment behind the needle plane, starts 1 on its active motion during which it picks up the thread loop left behind during the return stroke of the blind stitch needle 60, conveying it to the stationary loop catcher 68 along a curve initially ascending. The chamfer-on the projection protruding over the slot 61d of the small guide plate then takes charge of the secure guidage of the lower thread 100p portion below the noseshaped catcher 13 of the loopcatcher E8. The

upper portion of the thread loop is laid around the loop holder pin 14, provided on the noseshaped loop catcher 13, by means of the small foot 63a of the looper 63 which--owing to the support of the rotary bolt 65 described-reaches its terminal position by way of a somewhat steep ascending curve. This phase of operation is shown in Fig. 11. At the subsequent active operation of the blind stitching needle (iii the small foot 63a of the receding looper 63 releases the loop, which narrowed by the tension of the thread, glides off from the nose-shaped catcher 13 of the loop catcher 68, rounded off in front and below, and is fixed and tightened by the connecting stitch being the result of the subsequent through-stitch. If after the completion of the operating phase, visible in Fig. 11, the work is to be interrupted and the piqued fabrics are to be removed, same need but be drawn out in the fabric feeding direction :1: after the fabric bender casing 11 will have been lowered by the ull mem- 8. her 8| operated by means of the knees. Then the thread loop, prevented'by the holding pin 14 of the nose-shaped catcher 13 from gliding from the small looper foot 63a is automatically ruptured at its front edge so that an undoing of thepi'qu seam is avoided. In this connection the-blind stitching needle is saved from bending in the fabric feeding direction by the additionalabutment on the small guide plates 10, 1|.

Having now particularly described, and ascertained the nature of my said invention, andain what manner the same is to be performed, I declare that what I claim is:

l. A blind stitch and piqu device, whether adapted for use as a self-contained machine or as a sewing machine attachment, which comprises, in combination with work feeding and bending means, a looper for forming a thread loop, a blind stitch needle, 2. presser part adapted to clamp the work and separating the work from the looper, said presser part having an opening for the work to be sewn and a groove for guiding the needle, a loop catching nose being provided in the edge of said opening for stripping the thread loop from the looper and laying it above and below the needle guiding groove.

2. A device as set forth in claim 1, in which the loop catching nose has a recess extending below the needle guiding groove.

3. A device as set forth in claim 2, in which the loop catching nose has a boss extending-above the needle guiding groove.

4. A device as set forth in claim 1, in which said presser part has a depression for the thread.

in front of the loop catching nose.

5. In combination with a machine head, 'a blind stitch and pique device, comprising a looper for forming a thread loop, a blind stitch needle, a presser part rigidly connected to the machine head and separating :the work from the looper, said presser foot having an opening for the work to be sewn and a groove for guiding the needle and a loop catching nose provided at the edge of said opening for stripping the thread, loop from the looper and laying it above andbeloyv the needle guiding groove, said loop catching nose having a thread holding pin which protrudes beyond the upper edge of said noser 6. A device as set forth in claim 5, in' w'l ichv a. A device as set forth in claim 5; in which one of the edges of the loop catching nose forms the front limit of the needle guiding groove, and in which the bottom part of thethread holding pin is bevelled off in the work feeding direction, a guiding. surface for the lower leg of the loop being providedbehind said edgev of the loop catching nose.

9. A device as set forth in claim 8, in which the presser foot has a longitudinal opening for the work feeding and bending means and in which the guiding surface forthe lower part of the loop extends laterally beyond said opening,

10. In combination with a machine head, a'

blind stitch and pique device,.comprising a looper for forming a thread loop, a blind stitch needle, a presser part rigidly connected to the machine head and separating the work from the. looper,

said presser foot having an opening for the work to be sewn and a groove for guiding the needle and a loop catching nose provided at the edge of said opening for stripping the thread loop from the looper and laying it above and below the needle guiding groove, said loop catching nose having a thread holding pin which protrudes beyond the upper edge of said nose, the looper being pivotally movable about an axis which is inclined both against the Vertical plane of the needle path and against a vertical plane laid through the nadir point of the needle path in the work feeding direction, the pivotal axis of the looper intersecting with the needle path on 10 the stitching-in side of the work, the looper thus being adapted to lay the upper leg of the loop around the thread holding pin.

FRANZ MIKOLAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,248,439 Scheibel July 8, 1941 2,257,363 Arver Sept. 30, 1941 

